We have been studying the biological significance of both the antigen on human and murine tissue revealed by neuraminidase treatment and its antibody. In humans this antibody titer can be boosted by influeza virus infection. This virus possesses neuraminidase. We are investigating possible lymphocyte mitogenic properties of the antibody, and we are searching for the natural occurrence of the antigen on tumor tissue. HLA antigens have been associated with a variety of diseases. Our studies concentrate on malignant diseases and disorders of immunity. We are testing the hypothesis generated by our previous work that long term survival in leukemia and lung cancer is due to the possession of certain HLA antigens. Other diseases studied include melanoma, gluten-sensitive-enteropathy, dermatitis herpetiformis, acute schizophrenia and manic-depressed psychoses.